Automated spray cleaning apparatus for semiconductor wafers

ABSTRACT

Semiconductor wafer ( 11 ) are uniformly and thoroughly cleaned of particulate and organic contaminants by sweeping the wafer with a hydraulic broom that sprays cleaning solution onto the wafer. The broom contains an aspirating nozzle ( 3 ) for connection to a source of pressurized gas, such as nitrogen, and to a source of cleaning fluid, such as acetone, wherein cleaning fluid aspirated by the gas stream is expressed through the nozzle outlet to impact the surface of the wafer, dislodging particulate matter and dissolving organic contaminants. A programmed controller ( 9 ) controls movement of the hydraulic broom relative to the wafer to ensure that the entire surface is cleaned and permits a variety of sweeping patterns.

FIELD OF THE INVENTION

[0001] This invention relates to cleaning of semiconductor wafers,including Germanium, Silicon and all other semiconductor compounds, suchas Gallium Arsenide (“GaAs”) and Indium Phosphide (“InP”) and, moreparticularly, to a method and apparatus for thoroughly spray cleaningthe surface of semiconductor wafers of particulate and organiccontaminants in a manner that assures uniform and reproduciblecleanliness of each wafer cleaned.

BACKGROUND

[0002] Semiconductor devices are typically fabricated on single crystalwafers of semiconductor materials using photo-lithographic mask and etchor ion-bombardment techniques. Typically the wafer contains a largenumber of semiconductor devices which are fabricated simultaneously.Initially, and at the completion of each step in the semiconductorfabrication process, some residue remains; the kind or type of residuebeing in part dependent on the stage of fabrication processing, and thewafer surface must be cleaned in preparation for a succeeding step.Depending upon the particular process step in the semiconductor devicefabrication process being completed, the completion of a particularprocess step may incidentally also produce particulate debris, organiccontaminants and/or unwanted pieces of thin film metallization layers onthe surface of the semiconductor wafer. The residue, particulate debris,organic contaminants and metal pieces must be removed before proceedingwith the next step in the fabrication process.

[0003] Mass produced semiconductors typically employ silicon technologyand cleaning equipment exists to handle such mass production. Suchcleaning equipment, however, is unsuited to semiconductors that use theIII-V compounds identified in the Periodic Table of the Elements, suchas InP and GaAs. First, cleaning solvents used for cleaning siliconwafers are either strong acids or strong bases, which are very harshchemicals inappropriate for InP and GaAs wafers and produces a loweroverall cleanliness. As an advantage, the present invention avoids harshchemicals detrimental to the wafer. Second, the semiconductor chipsproduced on silicon wafers are not as fragile as the semiconductor chipsfabricated on InP or GaAs wafers. Certain cleaning apparatus designedfor cleaning of silicon wafers, such as brush scrubbing, producesstructural damage when applied to cleaning of semiconductor devicesconstructed on InP or GaAs or other compound semiconductor wafers,especially for wafers containing gold metallization layers. As anadvantage, the present cleaning system is less harmful mechanically tothe semiconductor chips on the wafer.

[0004] Accordingly, a principal object of the invention is to cleanwafers fabricated of compound semiconductors in a uniform andreproducible manner.

[0005] Another object of the invention is to clean Silicon and Germaniumwafers or other types of substrates that employ devices or structuresthe could be damaged by application of conventional cleaning techniques.

[0006] A further object of the invention is to minimize and conserve theconsumption of solvent and reduce the hazardous waste generated in thesemiconductor cleaning process.

[0007] A still further object of the invention is to provide a computercontrolled wafer cleaning apparatus that assures that each wafer cleanedis cleaned exactly alike.

[0008] And still another object of the invention is to provide anautomated wafer cleaning apparatus that is relatively inexpensive tobuild and operate, may be constructed of “off-the-shelf” components, iseasy to maintain, and may operate in an essentially unattended manner.

SUMMARY OF THE INVENTION

[0009] In accordance with the foregoing objects and advantages,semiconductor wafers are cleaned by moving a hydraulic broom about thesurface of the wafer to sweep the wafer clean, the pressurized fluidissuing from the hydraulic broom being of a character that dissolvesorganic solvents as may be present on the surface of the wafer andproduces the mechanical force to dislodge particulate debris from thewafer. In accordance with a specific aspect to the invention, thehydraulic broom is formed of an aspirated sprayer which combines gasreleased from a pressurized source of gas, suitably nitrogen, through anozzle and aspirating the cleaning fluid, suitably acetone, through thenozzle into the gas stream providing a source of pressurized cleaningfluid expressed from the nozzle.

[0010] The cleaning system is automated. In one embodiment a three-axispositioner, under control of a programmed controller, controls the sweepof the hydraulic broom, moving the broom in a predefined “scanning”pattern over the wafer surface. As an advantage, the pattern of scan maybe changed, the number of cleanings of an individual wafer may bechanged, and the orientation of the wafer may be changed to permit asurface sweep in an alternate direction. In another embodiment polarmovement is employed rotating the wafer while simultaneouslycontinuously pivoting the broom over a predetermined arc about a pivotaxis and linearly translating the position of that pivot axis.

[0011] The foregoing and additional objects and advantages of theinvention together with the structure characteristic thereof, which wasonly briefly summarized in the foregoing passages, will become moreapparent to those skilled in the art upon reading the detaileddescription of a preferred embodiment of the invention, which follows inthis specification, taken together with the illustrations thereofpresented in the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In the drawings:

[0013]FIG. 1 illustrates a wafer cleaning system in accordance with theinvention;

[0014]FIG. 2 illustrates a preferred routing program of the relativemovement of the wafer and spray nozzle elements in the operation of theembodiment of FIG. 1;

[0015]FIG. 3 illustrates another less preferred routing of the relativemovement of the wafer and nozzle elements in the embodiment of FIG. 1;

[0016]FIG. 4 is a spray box that houses the principal components of thecleaning system, depicted in a left perspective view and

[0017]FIG. 5 is a right perspective view of the spray box of FIG. 4;

[0018]FIG. 6 illustrates a vacuum chuck component of the invention usedto hold a wafer, shown from the left side in a withdrawn position fromthe housing; and

[0019]FIG. 7 illustrates the vacuum chuck component of FIG. 6 from theright side;

[0020]FIG. 8 illustrates the foregoing spray box of FIG. 4 and thevacuum chuck of FIG. 6 in a front view with the vacuum chuck extendingthrough the door way of the spray box;

[0021]FIG. 9 shows the aspirating nozzle element of the system;

[0022]FIG. 10 is a side view of the aspirating nozzle of FIG. 9 and theassociated support structure;

[0023]FIG. 11 partially illustrates the wafer cleaning system in a topview overall with the walls of the spray box being treated astransparent;

[0024]FIG. 12 partially illustrates the wafer cleaning system of FIG. 11in side view;

[0025]FIG. 13 partially illustrates the wafer cleaning system of FIG. 11in front view;

[0026]FIG. 14 is a block diagram of the additional controls employed inthe practical embodiment of FIGS. 4-13;

[0027]FIG. 15 illustrates an alternative nozzle and support structureassembly to that shown in FIG. 10;

[0028]FIG. 16 illustrates another embodiment of the invention thatcombines the features of a number of alternative embodiments; and

[0029]FIG. 17 illustrates the movement undertaken by the nozzle andvacuum chuck elements of one of the embodiments of the inventionincluded in FIG. 16 and is presented to aid in the description ofoperation.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0030] Reference is made to the pictorial illustration of FIG. 1,illustrating a wafer cleaning system constructed in accordance with theinvention. The cleaning system includes a vacuum chuck 1 and a fluidnozzle 3 that are coupled, as hereafter described in greater detail, toa three axis positioner 5, X-axis, Y-axis and theta (rotation) axispositioning, all of which components are contained within a housing 7,represented by dash lines, and a programmed controller 9 that controlsoperation of the positioner.

[0031] A semiconductor wafer 11, represented as having a rectangulargeometry is illustrated seated upon chuck 1, for the purpose ofassisting in the description of operation, later herein presented, itbeing understood that the wafer is not a component of the apparatus, butis to be acted upon by the apparatus. For purposes of discussion thesides of the wafer labeled “a” and “b” are designated as the front andback edges of the wafer, respectively, and the sides labeled “c” and “d”are designated as the left and right side edges, respectively, of thewafer. The foregoing designation is arbitrary and is solely for thepurpose of providing reference locations helpful in the description ofoperation of the invention.

[0032] Positioner 5 is controlled by a programmed controller 9, whichmay be a micro-controller that is operated in accordance with ahard-wired program in read-only memory (“ROM”) or a general purposecomputer programmed with software to carry out the described functions.The positioner is illustrated as a servo-motor driven belt type systemfor the X and Y axis positioning and a pneumatic stepper motor for theta(rotation).

[0033] In such a positioner a continuous loop belt 10 is supportedbetween a pair of pulleys 12 and 13, and the belt is moved by aservo-motor 15 that turns the pulley 13. A bracket 17, which is slipmounted to a straight rail 16, oriented horizontal in the figure, thatsupports the weight of the bracket, and, in turn, also the weight of theobject to be positioned along the X-axis, which is nozzle 3 in thisembodiment, is coupled to a position along the belt. When belt 10 movesa predetermined distance, back or forth (along the X-axis), the beltpulls bracket 17, which functions as a traveler, the same distance.

[0034] The positioner includes a second continuous loop belt 19 mountedbetween a pair of pulleys 20 and 21 with the rotational position ofpulley 21 being controlled by a second servo-motor 23. A bracket 25,which is slip mounted to a rail 27, vertically oriented in the figure,that supports the weight of the bracket, and, in turn, also the weightof the object to be positioned along the Y-axis, which in thisembodiment includes vacuum chuck 1 and some additional elementshereafter described, is coupled to a position along the belt 19. Whenbelt 19 moves a predetermined distance, back or forth (along theY-axis), the belt pulls bracket 25, which functions as a traveler, thesame distance.

[0035] The positioner also includes a rotational axis position controlfor the object that is to be rotationally positioned, here the objectbeing the vacuum chuck 1 (and any wafer 11 that may be held by thechuck). The rotational or, as variously termed θ, positioning isrepresented in the figure by a pneumatic stepper motor 29, alsocontrolled by controller 9 via an electric gas valve 30, and a gear 31that engages the gear teeth, not illustrated, of a rotational table, notillustrated, that supports vacuum chuck 1. Stepper motor 29, the gearand rotational table are also supported and carried by bracket 25. Aflexible gas hose extends from valve 30 to the stepper motor.

[0036] Valve 30 connects via a gas line 32 to a source of pressurizedgas, not illustrated, suitably the same gas source as is used for nozzle3, as later herein described. Controller 9 connects to gas valve 30 viaelectrical leads. The controller controls the opening and closing of gasvalve 30, and, hence, the supply of pressurized gas to operate steppermotor 29.

[0037] Controller 9 thus controls the X-axis position of nozzle 3 andthe Y-position and angular position of vacuum chuck 1 by supplying theappropriate signals to each of the servo-motors and pneumatic steppermotor in accordance with the program that the controller is to follow.As those skilled in the art appreciate, computer controlled positionersof the foregoing type are available off-the-shelf and may be adapted foruse in the practice of the invention.

[0038] Further, although the foregoing embodiment employs a belt-pulleyarrangement other types of positioners are available that employ wormscrew type arrangements instead. However, with any such positioner caremust be taken to avoid any structure that could generate A spark, sincethe environment is volatile and flammable. As is appreciated, theinvention may incorporate any type of three-axis programmable computercontrolled positioner.

[0039] Nozzle 3 is an aspirating nozzle. The nozzle is connected by aflexible gas hose 4 to a source of pressurized gas, not illustrated,such as nitrogen. The nozzle is also connected by a flexible fluid hose6 to a reservoir or source of solvent fluid, not illustrated, such asacetone, which is preferred. The bracket 17 supports the nozzle at avertical elevation above the surface of wafer 11, with the latter isseated on chuck 1. The height of the nozzle, i.e. The Z-axis position,is preferably manually adjustable (as later herein described in greaterdetail), and is adjusted to be at a higher elevation than the vacuumchuck 1 and any installed wafer 11. Additionally, the nozzle ispositioned with the nozzle axis inclined to the surface of the vacuumchuck 1 and, hence, is inclined to the surface of the wafer 11 that isto be installed and cleaned.

[0040] For operation, wafer 11 is seated on the vacuum chuck 1 inhousing 7 with the front edge of the wafer aligned with the X-axis,parallel to rail 19, and the vacuum source, not illustrated is connectedto the chuck to hold the wafer in place. Controller initializes andpositions the end of nozzle 3 at the reference 0,0 position set by thedesigner of the controller program, as example, at the lower left cornerof wafer 11 in FIG. 1 or, with an aspirating sprayer as in the preferredembodiment, just below the lower left corner of the wafer.

[0041] In an aspirating nozzle, such as nozzle 3, a high velocity streamof gas flows past a fluid inlet in the nozzle and out the nozzle exit.With the fluid inlet connected to a source of fluid, the streaming gaslowers the pressure over the inlet and fluid is forced up through theinlet, and into the stream of gas, the known phenomena of aspiration.The aspirated fluid then travels with essentially the same velocity andpressure as the gas, and out the nozzle exit. The volume or rate atwhich the fluid is drawn up may be adjusted by adjusting the size of theinlet, which may be accomplished manually. With both the solvent fluidand the source of gas connected to the nozzle, the nozzle expresses anaspirated spray of fluid, hereafter sometimes referred to as a fluidjet. Initially, the output of the nozzle is gas, but quickly aspiratesthe solvent fluid. Hence, except where noted to the contrary the fluidjet is understood to contain both solvent fluid and the gas.

[0042] Because the nozzle being used in the preferred embodiment is anaspirating type nozzle, that which exits from the nozzle when the systeminitially is operated is a blast of the aspirating gas. After a fewmoments the fluid solvent is drawn up and the fluid jet is thenexpressed from the nozzle. To avoid having the initial gas jet directedonto the wafer surface for reasons later discussed, it is preferred tomake the first steps of the spray pattern, namely the first left toright movement (horizontal movement in the figure), be directed slightlyin front of the bottom edge of wafer 11 so that the gas stream does notimpact the wafer surface. Additionally, an anti-siphon valve may beincorporated in the system to reduce fluid depletion when the system isidle.

[0043] The controller is programmed to move the relative position of thenozzle and wafer in accordance with the pattern of FIG. 2 to whichreference is made. As shown in the figure, the nozzle is to follow apath from left to right directing a fluid jet onto the wafer as thenozzle moves. When the right side of the wafer is reached (orthereafter), the direction of the nozzle movement is reversed and,simultaneously, the relative vertical position from the bottom edge ofthe wafer is increased one small increment. The nozzle then moves fromright to left spraying solvent fluid and gas at the wafer along ahorizontal path parallel to the prior path taken.

[0044] When the left side edge of the wafer is reached (or thereafter),the direction of movement of the nozzle is again reversed, moving fromleft to right, and the vertical level, the distance from the front edgeof the wafer, is again increased by an increment. The foregoing movementis repeated as many times as is necessary for the jet of solvent fluidto at least reach the upper right back corner of the back edge of thewafer (and may extend beyond that horizontal position) at which positionwafer cleaning may conclude (or as later herein described be put throughadditional cleaning). Programming the controller to accomplish theforegoing pattern (and any other desired pattern) of movement iselementary to those skilled in the programming arts, the details ofwhich are not necessary to an understanding of the invention.

[0045] Returning to FIG. 1, as thus programmed, during initialization ofthe positioning system, the controller supplies the appropriate signalto valve 30 releasing a sufficient number of gas pulses to stepper motor29 to ensure that the stepper motor positions the zero degree rotationalorientation of vacuum chuck 1 to the zero or reference position, if notalready at that rotational position.

[0046] Controller 9 supplies a signal to servo-motor 15 that moves belt11 to the left, and, hence, bracket 17 and nozzle 3, so that the nozzleaxis lines up with the left side, side “c” of the wafer, the zeroX-reference position. Controller 9 also supplies a signal to servo-motor21 that moves the belt 19, and, hence, bracket 25 and vacuum chuck 1,forward in the figure, so that the front edge “a” of wafer 11 alignswith the Y-axis zero reference position. At that reference position, thefluid jet issuing from the elevated end of nozzle 3 strikes the surfaceof the wafer at a position just in front of the front edge of the wafer,for reasons earlier discussed. With other types of sprayers, theposition of the strike would be at the front edge. As a practicalmatter, the distance is at most a minute distance from the front exitend of nozzle 3, and, one may state (with acceptable slight inaccuracy)that the front end of the nozzle 3 essentially lies on the Y-axis zeroreference position.

[0047] The controller then starts the sweeping procedure, supplyingpositioning information to move the nozzle 3 from the left to the rightside edge of the wafer. When the right side edge is reached, thecontroller supplies a signal to the Y-axis servo motor 29 to move thevacuum chuck 1 a predetermined small increment downward (in the figure),placing the end of nozzle 3, as example, a small distance above thefront edge of the wafer; and the controller thereafter supplies signalsto the X-axis servo-motor 13 to continuously move the nozzle parallel tothe X-axis to the left. When the nozzle moves to at least the left edge,the controller again operates the Y-axis servo motor to move the chuckdownward (in the figure) an additional increment and reverses thedirection of travel of nozzle 3, which proceeds from left to right. Theforegoing operation continues until the fluid jet from the nozzlereaches at least the upper right hand corner of wafer 11. In theforegoing manner the fluid jet from the nozzle is applied to the surfaceof the wafer from side to side and from front to back of the wafer,covering the entire surface of the wafer.

[0048] As earlier noted, the axis of nozzle 3 is inclined to the surfaceof the wafer 11 and vacuum chuck 1, while the nozzle is elevatedslightly above the surface of the wafer. The incline may at an angleselected from a range of about twenty degrees to seventy degrees. Theaspirated spray of solvent fluid is expressed from the nozzle underconsiderable pressure, the pressure of the aspirating gas stream, and ata high velocity. The fluid jet strikes the surface of the wafer askancewith considerable impact. Should a particle (or particles) be present onthe surface and be struck by the fluid jet, the fluid exerts a forcesufficient to push the particle (or multiple particles) forward alongthe surface of the wafer. The particles are pushed forward in the samedirection as the nozzle travels relative to the surface of the waferand, hence, the fluid jet. Hence, as the nozzle continues movementtoward the back edge of the wafer in the line by line movement, theparticles as may have accumulated on the disk (and not pushed off) arepushed further forward by force of the jet. As the nozzle moves alongthe back edge of the wafer, any accumulated are eventually pushed offthe back edge of the wafer and fall onto the vacuum chuck and/or to thebottom of housing 7.

[0049] In pushing particles forward, the nozzle, in effect acts as abroom, albeit, a hydraulic one. By routing the hydraulic broom over thesurface, the broom sweeps the surface of the wafer. The foregoing actionresembles the process used by one to sweep fallen leaves from one's homedriveway by “hosing down”, cleaning, one's driveway with a stream ofwater from the garden hose, another hydraulic broom.

[0050] If desired, the controller may be programmed to have thehydraulic broom travel a predetermined distance beyond the side edges ofthe wafer and/or the front and back edges of the wafer. Although doingso perhaps somewhat simplifies the programming of the controller, theextra movement beyond the edges of the wafer serves no purpose and isnot preferred. The extra movement increases the time taken to sweep thewafer. Such extra relative movement of nozzle 3 delays the cleaning ofthe next wafer to be cleaned and thereby delays production.

[0051] As those skilled in the art appreciate, the spray of fluidsolvent creates a considerable amount of splashing upon striking thewafer surface. The splashed fluid, however, is confined within housing7, and serves to clean particles from the exposed portions of the vacuumchuck not covered by the wafer, and washes down to the bottom of thehousing.

[0052] The foregoing programming of controller 9 to accomplish therouting of nozzle 3 relative to the surface of the wafer during cleaningis a preferred routing. Other routing may be substituted in the practiceof the invention, even if that routing is less preferred. As example,the controller may be programmed to route the nozzle in the zig-zagpattern illustrated in FIG. 3 to which reference is made. In order tofollow the zig-zag path the nozzle must be moved not only along theX-axis, but simultaneously along the Y-axis as well. Returning to FIG.1, for the foregoing zig-zag routing, controller 9 supplies signals toboth servo-motor 15, which drives the nozzle movement along the X-axisconcurrently with servo-motor 23, which drives the vacuum chuck alongthe Y-axis (or as alternatively viewed moves nozzle 3 in the Y-directionrelative to chuck 1), but at a lesser incremental movement.

[0053] In the preceding discussion, wafer 11 has been describedimplicitly as having a relatively flat surface, which is accurate asviewed on a macroscopic level. On the microscopic level however, thesurface of the wafer during fabrication of semiconductor chips acquiresa definite topology of some regions that are vertically higher thanother regions. Fabrication of the chips on the wafer involves producingmultiple layers of metals, and differently doped layers of semiconductormaterials, which is accomplished in multiple fabrication steps. Uponcompletion of each step, the wafer must be cleaned before beginning thenext step or stage of fabrication. In the later stages of chipmanufacture, the surface of the wafer contains a definite topology.

[0054] When cleaning the wafer in the later stages of semiconductor chipfabrication, a possibility exists that the fluid jet will be unable toforce a microscopic size particle up over an adjacent a microscopic size“wall” or may press the particle against that wall when that wall liesperpendicular to the direction of the solvent fluid jet from nozzle 3.Hence, despite the foregoing cleaning, the wafer may retain someparticles and thereby remain unclean. By reorienting the wafer toanother angle, such as by reorienting the wafer by ninety degrees, theforegoing wall will then lie parallel to the direction of the fluid jet.In that orientation, the fluid jet will easily push the particle forwardalongside the wall.

[0055] As an additional feature, the present invention provides forrotating the wafer to another angular position so as to minimize oravoid retaining microscopic particles due to the foregoing microscopicwalls in the wafer. Reference is again made to FIG. 1. During thedescribed line-by-line cleaning operation, the forward edge “a” of thewafer is located at a lower horizontal position in the figure than therear edge “b” and nozzle 3 essentially traveled from the lower leftcorner of wafer 11 to the upper right corner of the wafer.

[0056] When controller 9 determines that the wafer cleaning procedure iscompleted, that is, according to the tracking of the program by thecomputer (in lieu of active position monitoring) nozzle 3 shouldessentially be located at the upper right corner of the wafer (formed atthe juncture of sides “b” and “d” in the figure), controller 9 suppliesappropriate signals to electrically operated gas valve 30, which inturn, supplies gas pulses to the theta pneumatic stepper motor 29,commanding the stepper motor 29 to rotate clockwise, as example, by anangle of ninety degrees. Stepper motor 29 then rotates the vacuum chuck1 about the axis of the chuck by ninety degrees. Since wafer 11 ispositioned with the axis of the wafer coaxial with the axis of thechuck, the wafer is reoriented so that side “d” is now the lower mosthorizontal edge, a forward side to the wafer, and side “a” ispositioned, vertically in the figure, as a left side edge of the wafer,replacing side “c” in that position.

[0057] Concurrently, controller 9, operating servo-motors 15 and 23,repositions the vacuum chuck 1 and the nozzle 3 (as in theinitialization procedure earlier described) so that the fluid jet fromthe nozzle is again directed at the lower left corner of therepositioned wafer 11 and repeats the cleaning process which was earlierdescribed and need not be repeated.

[0058] Although the foregoing embodiment rotationally repositions wafer11 only once and by ninety degrees, as is recognized by those skilled inthe art, controller 9 may in alternate embodiments be programmed torotate the wafer by any other angle several times, repeating thecleaning process each time. As example the program may call for rotatingthe wafer by an increment of 45 degrees each time the cleaning processis completed, re-run the cleaning process and to perform such rotationsand re-run the cleaning process two additional times, a total of 135degrees, before concluding the cleaning procedure for the wafer.Although such a program is within the scope of the invention, thealternative programs are less preferred as they require additional timefor cleaning and, thus slow down the semiconductor fabrication processand appear to go beyond the point of diminishing return in cleaning.

[0059] In the foregoing embodiment the rotation of the vacuum chuck wascontrolled by a pneumatic motor 29. It is appreciated that other meansmay be substituted for that type of motor, as example, a brushlesselectric motor, such as a servo-motor, such as used for motors 15 and23.

[0060] On concluding the cleaning of a wafer, the controller halts theoperation and extends the water chuck beyond the housing so that thecleaned wafer may be removed. Another wafer may be loaded for cleaningby aligning the wafer in the chuck so that the axis of the wafer ispreferably aligned with the chuck axis and an edge of the wafer isaligned with the Y-axis traveled by nozzle 3.

[0061] The foregoing structure and additional structure as may beincluded in a practical embodiment of the invention is next considered.For convenience the denominations used to identify components in theembodiment which follows are the same that were used in connection withthe same components found in the embodiment of FIG. 1. Reference is madeto FIGS. 4 and 5 which illustrate housing 7. The housing includes abottom hinged front door 34, which pivots open like an oven door, toprovide access, and, above the door, a glass or transparent plasticwindow 35, through which personnel may view the wafer during thecleaning operation. Preferably, the door is pneumatically operated undercontrol of the programmed controller.

[0062] Hose 37 supplies pressurized nitrogen to open hinged door 34 andhose 38 supplies pressurized nitrogen to close that door. Hose 36supplies acetone to the external drip 47, which is attached to theenclosure. Hose 39 attaches to an appropriate exhaust vent, notillustrated, at the rear of the housing, and connects to the facilitygas exhaust system, which typically may be a thermal oxidizer forsolvent use or a fume exhaust for a non-solvent use. The shieldedelectrical conduit 40 is the electrical signal interface from thecontroller 9 to the x-axis stepper motor. Hose 41 supplies pressurizednitrogen to purge or vent the plenum in which the brushless X and Y-axisstepper motors are located. The housing may be fabricated of stainlesssteel or aluminum. Automated wafer cleaning is accomplished inside thehousing, which contains the splashing of the solvent fluid to the closedinternal region of the housing.

[0063]FIGS. 6 and 7 illustrate vacuum chuck 1 from the left and rightsides, respectively, in a position withdrawn from housing 7 forinsertion or removal of a wafer. Conveniently, when door 34 isautomatically lowered, as later herein described, the vacuum chuck isadvanced forward out of housing 7 to the illustrated “home” position.Hose 42 is the vacuum hose that supplies the suction on the uppersurface that holds the wafer in place. Hose 43 is the gas hose to thepneumatic stepper motor, not visible in the figure. The outer surface ofstepper motor 29 and bracket 25 are more visible in FIG. 7.

[0064] The vacuum chuck is seen in a top perspective view in FIG. 9 towhich reference is made. A conduit 47 is shown attached to the front ofhousing 7. The conduit contains an open end positioned over the centerof the surface of the vacuum chuck, when the latter is in the extendedposition shown in the figure. The conduit connects to a pressurizedreservoir of the acetone cleaning fluid supplied in a common acetonedistribution manifold as may be located immediately behind theenclosure. The conduit is calibrated to drip acetone fluid onto thevacuum chuck and/or wafer placed on the chuck and is referred to as theexternal acetone drip. The cleaning fluid keeps the organic contaminantson the wafer from drying, which would make those contaminants moredifficult to remove in the cleaning process.

[0065]FIGS. 8 and 10 illustrate the spray apparatus in perspective andin side view, respectively. Nozzle 3 is supported to the inverted “L”shaped bracket 17 by adjustment brackets 49 and 50. The bracket arms 49are pivotally connected together at pivot axis 51. The nozzle is clampedbetween the two arms by clamping members 52 attached to the upper end ofthe arms 49. As illustrated, the nozzle 3 contains a long generallycylindrical body. The upper end contains a valve mechanism 54 thatpermits manually adjusting the force of the fluid spray or jets thatissue from the opening at the lower end. Nozzles of the foregoing typeare available from various sources as an off-the-shelf item. Bracket arm50 contains a slotted upwardly extending curved guide arm 53. The curvedslot is a sector of a circle. Arm 49 is pivoted to the appropriate angledesired relative to the horizontal, suitably between about twenty toseventy degrees in the preferred embodiment, and the arm 49 is securedto that position of the guide arm 53 by tightening a bolt and nutthrough the slot. The nozzle may be moved along the nozzle axis 56either forward or backward prior to tightening the clamping members 52to either reduce or increase the distance from the nozzle end to thesurface of the vacuum chuck, hence, to the wafer. The foregoingconstitutes a manual Z-axis adjustment.

[0066]FIG. 11 illustrates the wafer cleaning system in a top view; FIG.12 illustrates that system in side view and FIG. 13 is a front view ofthe wafer cleaning system. In the latter three illustrations the housingis rendered as transparent with the outline of the housing elementsillustrated in order to permit view of the internal components. All ofthe elements earlier described contain the same denomination as in theprevious figures.

[0067] In FIG. 13 a drain 57 is included on the bottom of the housing.The drain is connected to an appropriate solvent collection tank in thefacility. All of the particles removed, and dissolved organic materialand acetone fluid during cleaning is removed from the housing assemblythrough that drain.

[0068] As an added feature, the door 34 to housing 7 is controlled by apneumatic motor, not illustrated. Reference is made to FIG. 14 which isa block diagram of the control circuit and additional apparatus for thisfeature. As shown the programmed controller 9 incorporates an operatorselection key pad. To start the operation the operator need onlymomentarily depress the start switch associated with the cleaningprogram that is to be run (only one being illustrated in the figure). Atthe conclusion of cleaning the controller is programmed to output aperceptible signal to personnel as at alarm 61. Responding to thatsignal the personnel, would then depress the exit key. The controller isprogrammed to respond to the depression of the exit key by issuing asignal to the door motor to open the door. Door 34 then opens, such aswas illustrated in FIGS. 6-8. The controller is also programmed tofollow the door opening to move the vacuum chuck 1 to an extendedposition outside the housing as shown in the cited figures by supplyingthe appropriate signal to the Y axis servo-motor. Referring to the topview of FIG. 11, one may observe that the belt 19 and rail in the Y-axisdirection extends to the front of the housing. By advancing the belt sothat bracket 25 moves to the far left in the figure, the vacuum chuck,located on a foot of the L-shaped bracket will extend out of thehousing. Lastly, the stop button permits the operator to halt thecleaning at any time at the operator's discretion.

[0069] In like manner, the cleaning system may be programmed to permitthe depression of the start button to initialize from the open doorposition just described. The operator may remove the cleaned wafer andinstall another wafer on the vacuum chuck. In the initializationprocedure following depression of the start program, the controller maybe programmed to move the vacuum chuck inside the housing 7, and thenrelatively move the nozzle and chuck as earlier described in thisspecification. The controller would then issue a signal to the doormotor to close the door. Cleaning would then commence.

[0070] In the practical embodiment, the nozzle 3 is placed about one tofive centimeters above the surface of the wafer; the axis of the nozzleis inclined at an angle of about 20 to 70 degrees to the surface ofwafer 11, as example, forty-five degrees. The fluid solvent expressedthrough nozzle 3 in the axial direction of the nozzle is under apressure of about 20 to 100 psi.

[0071] Acetone is a preferred solvent for cleaning of wafers, eventhough the fluid is flammable and in the vapors found in the operationcould be explosive. However, as is apparent from the description, thesystem avoids any component that might produce a spark. The systemincludes brushless motors, the servomotors, which do not contain anybrushes which are likely to produce sparks. The plenum in which thosemotors are located is purged with nitrogen supplied through hose 41. Thesystem also includes a pneumatically operated stepper motor. Lastly, theatmosphere within housing 7 is ventilated to an external ventilationsystem that draws off and disposes of any vapors harmlessly.

[0072] Although the invention has been described in connection with arectangular wafer, as one appreciates, the invention is not limited tocleaning of wafers that are of a square or rectangular shape. As thoseskilled in the art recognize the invention is capable of cleaning wafersthat may be of any shape. As example, assuming that the wafer is ofcircular or elliptical in shape, however unlikely it may be for one todesign such a wafer, the closest portion or point of the periphery ofthe wafer that is at the lowest vertical position in the figure shouldbe regarded as the front edge; and that portion or point at the highestvertical position in the figure should be regarded as the back edge orside of the wafer; and likewise the left side edge would be the point orportion of the periphery of the wafer located at the horizontal positionin the figure located closest to the left edge of the sheet; and theright side edge would be the point or portion of the periphery of thewafer located farthest horizontal position from the left edge of thesheet. As is apparent, the relative movement between the nozzle and thewafer provides a scan or sweep of the entire surface of such a circularor elliptical shaped wafer in the same manner as occurs with therectangular shaped wafer.

[0073] From the foregoing description, one recognizes that the movementof the hydraulic broom is relative movement. In the foregoingembodiment, the chuck carrying the wafer, and, hence, the wafer is movedin one axial direction and the nozzle is moved in an orthogonaldirection to produce the “sweeping” action of the nozzle in the X-Yplane over the entire surface of the wafer. As those skilled in the artappreciate, in other embodiments it is possible to retain the nozzlestationary and move the wafer in both the X and Y axial directions or,alternatively, hold the wafer stationary and move the nozzle spray inboth the X and Y axial directions over the X-Y plane of the surface ofthe wafer to produce the “sweeping” action of the nozzle in the X-Yplane over the entire surface of the wafer. From the standpoint of onestanding on the surface of the wafer, the person would observe thenozzle moving over the X-Y plane in each case. Each such embodimentsfalls within the scope of the present invention. Thus it should beunderstood that the term “moving” the nozzle (or, as variously termed,the hydraulic broom) over the surface of the wafer is intended to meanrelative movement as viewed from the perspective of the wafer as aconvenient reference location.

[0074] Further, as those skilled in the art appreciate, the foregoinginterpretation of movement of the nozzle (or, as variously termed, thehydraulic broom) over the surface of the wafer is equivalent to movingthe wafer in the axial X and Y directions across the nozzle exit. Thelatter is simply a change in perspective taken from the standpoint of anobserver placed on the nozzle who would view the movement of the waferthinking that the nozzle is stationary. The physical effect is the same.The foregoing falls within the scope of the present invention, which isindependent of the point of view one may take to describe the invention.The description herein and in the claims which follow of necessity areexpressed in terms taken from a point of view, and that point of view isfrom the surface of the wafer. That necessity of language is notintended to restrict the scope of the invention in any way.

[0075] In the preceding embodiment, the nozzle is supported on a bracketthat is manually adjustable, as illustrated in FIG. 10, to which briefreference is made. However, if it is desired to place the angularpositioning of the axis of the nozzle and the positioning of the heightof the nozzle tip under computer control, a more highly automated nozzleand support assembly, such as illustrated in side view of FIG. 15, maybe substituted. For convenience, the elements that are incorporated inthe assembly of FIG. 15 that correspond to elements in the manuallyadjustable assembly of FIG. 10 are identified by the same number,primed, and the description need not be repeated.

[0076] In this assembly, the arcuate slot is used merely as a guide forthe pivotal movement of bracket 49′, eliminating the nut of the clampingbolt associated with the slot. The platform 50′ is supported atop theinverted L-shaped bracket by a pneumatic actuator 58, pictoriallyillustrated. The movable portion of actuator 58 is attached to theunderside of the platform and is strong enough to support the entireassembly. Another pneumatic actuator 59, pictorially illustrated, ispivotally anchored to the upper surface of platform 50′ and itsextensible portion is attached to the bracket 49′ supporting nozzle 3′.

[0077] Actuator 58 is connected by hose 69 to an output peripheral ofcontroller 9, and actuator 59 is similarly connected by hose 68. Bycontrolling the pressure applied to actuator 58, the controller controlsthe vertical (Z-axis) position of the tip of nozzle 3′ above theL-shaped pedestal. Similarly, by controlling the pressure applied toactuator 59, the actuator is able to either pivot the bracket 49′, andnozzle 3′ to the left about the pivot point, increasing the angle α, theangle of tilt, or pivot the bracket down to the right in the figure,decreasing that angle.

[0078] A height sensor 60, pictorially illustrated, is connected to aninput, not illustrated, of the controller to provide feedback to thecontroller of the height. A tilt sensor 67, pictorially illustrated, isconnected to another input, not illustrated, of the controller andprovides feedback to the controller of the tilt angle. The controller isprogrammed to process the respective height and angle information,determine if the height and inclination are achieved and actuate therespective pneumatic adapters to do so.

[0079] The foregoing provides additional flexibility to the spraycleaning apparatus. As those skilled in the art appreciate, theforegoing controller-controlled adjustment devices presented in FIG. 15are merely illustrative. Alternative structures may be found or designedto produce the same functions, although they will differ in detail. Allsuch alternatives should be understood to fall within the scope of theinvention.

[0080] A number of additional modifications and improvements becomeapparent from an understanding of the foregoing description, which forsimplicity may be incorporated collectively in the illustration of FIG.16 to which reference is made. It may be noted that those elements inFIG. 16 that are the same as elements in the embodiment of FIG. 1 areidentified by the same number, primed. It is thus be unnecessary torepeat the structure and function of the corresponding elements in thisembodiment, which were earlier described.

[0081] In the prior embodiment, a pneumatic motor 29 was used toposition the spindle or vacuum chuck 1 at various angles of rotationunder control of the programmed controller 9. In this alternativeembodiment the pneumatic motor is replaced with another electric motor63 of a type that does not produce electrical sparks; and that motor iscontrolled by programmed controller 9′ as represented by the controlline leading thereto. Electric motor 63 may position the vacuum chuck atany angle of rotation, essentially performing the same functions aspneumatic motor 63 of the prior embodiment. However, in addition, thecontroller 9′ may provide a control input that requires electric motor63 to rotate or spin continuously for a predetermined durationprescribed by the program of the controller.

[0082] Such continuous rotation serves an additional function in thespray cleaner combination. Consider that the spray cleaning apparatus isused to spray clean wafer 11′ in the manner previously described. Uponcompletion of the spray cleaning of the wafer, it may be desirable todry the wafer, before removing the wafer from the apparatus.Accordingly, instead of being programmed to halt activity as in theprior embodiment, the controller 9′ is programmed to operate motor 63continuously for a selected interval. In so doing, the motor spinsvacuum chuck 1′ at a high rotational rate to spin-dry the wafer. Thehigh centrifugal force created by spinning forces any liquid on thewafer to be thrown off. Following completion of the foregoing spin dryoperation, the controller then terminates spray cleaning operation.

[0083] The embodiment of FIG. 1 contained a single spray nozzle. Afurther alternative embodiment of the invention may contain more thanone spray nozzle. Continuing with FIG. 15, a second spray nozzle 64 isincluded in the combination. That additional spray nozzle is supportedon a bracket that is joined to bracket 17′ that supports nozzle 3′, and,hence, moves in unison with the latter nozzle and vice-versa. Spraynozzle 64 is coupled by a flex hose to a source of de-ionized water (“DIwater”) and/or methanol as is indicated in the figure.

[0084] In such an embodiment controller 9′ is programmed to connect theDI water to the hose, through a valve, not illustrated, upon conclusionof the cleaning step described in connection with the operation of theembodiment of FIG. 1. The controller may be programmed to repeat therelative movement of nozzle 64 over the entire disk, as occurred in thecase of the spray cleaning or position the nozzle at a strategicposition relative to wafer 11′ and then allowed to remain open, sprayingout the DI water (or, as appropriate, methanol). The DI water (or, asappropriate, methanol) thereby rinses off wafer 11′. Preferably, thespray cleaning apparatus is constructed and programmed to include boththe additional nozzle structure and rinse cycle as well as thecontinuous spin motor and spin-dry cycle described in the immediatelypreceding paragraphs. In that way, following the spray cleaning of thewafer, the wafer is rinsed and spin-dried.

[0085] In a still further alternative embodiment controller 9′ isprogrammed to initially position spray cleaning nozzle 3′ at the centerof the vacuum spindle 1′ on commencement of the spray cleaning of wafer11′. Then motor 63 is commanded by controller 9′ to spin continuously sothat the wafer 11′ spins with a rotational speed from about ten to 500revolutions per minute. Concurrently, the controller slowly operatesmotor 15′ to move nozzle 3′ laterally to the right to the outer edge ofthe wafer. As one appreciates, the foregoing relative movement betweenwafer 11′ and nozzle 3′ is more of a polar coordinate system of movementin lieu of the Cartesian system described in connection with theoperation of FIG. 1.

[0086] As is apparent, the foregoing movement does not require movementof Y-axis positioner motor 20′. Were the polar movement the only type ofmovement required (or desired), a form of the apparatus could bedesigned that eliminated that positioner. However, the preferred form isto retain the Y-axis movement capability in a single apparatus to allowthe spray cleaning apparatus to possess a maximum flexibility forprogrammed operation.

[0087] In a still further alternative embodiment nozzle 3′ is supportedby a positioner motor 66′ that in turn is controlled by controller 9′ asrepresented by the control line. When energized, positioner motor 66′turns and thereby changes or adjusts the angular orientation of the axisof spray nozzle 3′. The foregoing structure is combined with thestructure and programming described in the paragraph before thepreceding paragraph. More specifically, controller 9′ is programmed toinitially position spray cleaning nozzle 3′ at the center of the vacuumspindle 1′ on commencement of the spray cleaning of wafer 11′. Thenmotor 63′ is commanded by controller 9′ to spin continuously so that thewafer 11′ spins with a rotational speed from about ten to 500revolutions per minute. Concurrently, controller 9′ slowly operatesmotor 15′ to move nozzle 3′ laterally to the right to the outer edge ofthe wafer and operates motor 66′ to periodically sweep nozzle 3′ over anangle of 180 degrees, back and forth.

[0088] The foregoing motion is illustrated in FIG. 17 to which referencemay be made. The nozzle is pivoted over an arc, the pivot point beingformed on a bracket, not illustrated. That allows the nozzle to bedirected in different directions. All the while the bracket, notillustrated, holding the nozzle and the pivot point is being carriedforward along the linear path indicated by dash lines. Simultaneouslythe vacuum chuck is being rotated about its axis at varying rates ω. Theforegoing angular reciprocation of the nozzle and its movement along theX-axis with simultaneous spinning of the vacuum chuck 1′ ensures a goodcleaning of the wafer.

[0089] In still further embodiments, nozzle 3 in the embodiment of FIG.1 may be replaced by multiple spray nozzles, each of which is connectedto the supply of fluid and gas to which nozzle 3′ is connected. Themultiple nozzles are spaced laterally so as to cover different portionsof wafer 11. Such an arrangement allows the surface of the wafer to becovered more quickly with the cleaning spray since the nozzles coverdifferent regions of the wafer surface. The wafer surface is cleanedwith less physical movement required of the nozzles. As a consequence,the slightly more complex combination permits more rapid processing or“throughput”.

[0090] As those skilled in the art appreciate, the cleaning apparatusmay be enhanced further by the incorporation of a suitable roboticssystem for loading and unloading of the wafer in the cleaning apparatus,such as the familiar cassette to cassette wafer transfer system, in lieuof the manual system described in connection with FIG. 1.

[0091] Lastly, the foregoing embodiments describe a cleaning system forspray cleaning wafers one at a time. As those skilled in the artappreciate, spray cleaning of a number of wafers may be accomplishedwith the invention by enlarging the housing for the apparatus andproviding multiple numbers of elements for handling multiple waferssimultaneously, all of which comes within the scope of the invention. Insuch a system, as example a plurality of vacuum chucks may be operatedin tandem by a single Y-axis positioner and a plurality of nozzles, oneor more associated with each of the plurality of vacuum chucks, aresupported by an X-axis position for joint movement, which is operatedunder control of a single controller. Each of the nozzles would beconnected to the fluid and gas hoses (described in FIG. 1) and thehousing is enlarged in size to accommodate all such elements. A wafermay be placed in each vacuum chuck, and cleaning operation commenced.The cleaning operation is essentially the same as described for cleaninga single wafer. A like tandem arrangement for cleaning a plurality ofwafers simultaneously may be employed for each of the alternativeembodiments previously described.

[0092] It is believed that the foregoing description of the preferredembodiments of the invention is sufficient in detail to enable oneskilled in the art to make and use the invention. However, it isexpressly understood that the detail of the elements presented for theforegoing purpose is not intended to limit the scope of the invention,in as much as equivalents to those elements and other modificationsthereof, all of which come within the scope of the invention, willbecome apparent to those skilled in the art upon reading thisspecification. Thus, the invention is to be broadly construed within thefull scope of the appended claims.

What is claimed is:
 1. An automated cleaning apparatus for cleaningsemiconductor wafers, comprising: a chuck for holding a wafer to becleaned; and a hydraulic broom for automatically sweeping said waferwith solvent fluid.
 2. The cleaning apparatus as defined in claim 1,further comprising: programmed controller means for controlling thesweep of said hydraulic broom.
 3. The cleaning apparatus as defined inclaim 2, further comprising: a base for supporting said hydraulic broomand said chuck; and wherein at least one of said hydraulic broom andsaid chuck are movably mounted to said base; and wherein said programmedcontroller means causes relative movement between said hydraulic broomand said chuck in a predefined pattern over the surface of said wafer.4. An automated cleaning apparatus for cleaning semiconductor wafers,comprising: a chuck for holding a wafer to be cleaned; a hydraulic broomfor automatically sweeping said wafer with solvent fluid; a base forsupporting said hydraulic broom and said chuck, wherein said hydraulicbroom and said chuck are movably mounted to said base; and programmedcontroller means for controlling the sweep of said hydraulic broom, saidprogrammed controller means comprising: a programmed controller; athree-axis positioner controlled by said programmed controller; saidthree-axis positioner including a first positioning motor forpositioning said hydraulic broom along a first axis of a Cartesiancoordinate system, a second positioning motor for positioning said chuckalong a second axis of said Cartesian coordinate system, and a thirdpositioning motor for controlling the angular position of rotation ofsaid chuck, said third positioning motor being positioned along saidsecond axis together with said chuck by said second positioning motor,wherein said programmed controller means causes relative movementbetween said hydraulic broom and said chuck in a predefined pattern overthe surface of said water.
 5. The cleaning apparatus as defined in claim4, wherein each of said first and second positioning motors comprise aservo-motor.
 6. The cleaning apparatus as defined in claim 5, whereinsaid third positioning motor further comprises a pneumatic steppermotor.
 7. The cleaning apparatus as defined in claim 6, wherein saidhydraulic broom further comprises: an aspirating nozzle, said aspiratingnozzle including a gas inlet for receiving pressurized gas, a fluidinlet for coupling to a reservoir of solvent fluid, and a nozzle outlet,wherein a stream of gas from said gas inlet through said nozzle outletaspirates solvent fluid from said fluid inlet into said stream toproduce an aspirated fluid spray at said nozzle outlet to impact saidwafer.
 8. The cleaning apparatus as defined in claim 7, wherein saidaspirating nozzle outlet includes an axis, and further comprising: aadjustable bracket for mounting said aspirating nozzle, said bracketincluding first adjustment means for setting said axis at apredetermined angle relative to the upper surface of said chuck and asecond adjustment means for setting said nozzle outlet at a desiredelevation, said desired elevation being greater than said elevation ofsaid upper surface of said chuck.
 9. The cleaning apparatus as definedin claim 8, wherein said predetermined angle falls in a range of twentydegrees to seventy degrees.
 10. The cleaning apparatus as defined inclaim 7, further comprising: a drip tube, said drip tube for connectionto a source of solvent for dispensing droplets of solvent onto saidwafer; said drip tube being mounted for movement with said hydraulicbroom and being located behind said broom, wherein said droplets ofsolvent drip onto portions of said wafer after said portions have beenimpacted by said aspirated fluid spray.
 11. The cleaning apparatus asdefined in claim 9, further comprising: a drip tube, said drip tube forconnection to a source of solvent for dispensing droplets of solventonto said wafer; said drip tube being mounted for movement with saidhydraulic broom and being located behind said broom, wherein saiddroplets of solvent drip onto portions of said wafer after said portionshave been impacted by said aspirated fluid spray.
 12. The cleaningapparatus as defined in claim 10, wherein said chuck further comprises avacuum chuck.
 13. The cleaning apparatus as defined in claim 10, furthercomprising: a housing for confining said base, said hydraulic broom,said chuck and said three-axis positioner during cleaning, said housingincluding a door for providing access to the interior of said housing, adrain for removing debris and solvent fluid from said interior duringcleaning, and a vent for removing vapors from said interior of saidhousing during cleaning; and further comprising: a second drip tube,said second drip tube being located over said door; said second driptube for connection to a source of solvent for dispensing droplets ofsolvent when said door is open.
 14. The cleaning apparatus as defined inclaim 13, wherein said door is electrically operated and controlled bysaid programmed controller; and wherein said programmed controllerincludes a keypad to permit operator selection of multiple programs,including a first button for initiating a cleaning program and a secondbutton for initiating an exit program, said exit program for producingopening of said door and movement of said chuck through said open doorto a withdrawn position outside said housing.
 15. The cleaning apparatusas defined in claim 3, further comprising a first motor for spinningsaid chuck, said first motor being controlled by said controller; 16.The cleaning apparatus as defined in claim 15, further comprising asecond motor for periodically pivoting said hydraulic broom over apredetermined arc, said second motor being controlled by saidcontroller.
 17. The cleaning apparatus as defined in claim 16, whereinsaid controller includes means for commanding said first motor to spinsaid chuck and, concurrently, said second motor to periodically pivotsaid hydraulic broom over said predetermined arc.
 18. The cleaningapparatus as defined in claim 8, further comprising: a first motor forspinning said chuck, said first motor being controlled by saidcontroller, and wherein said controller includes means for commandingsaid first motor to spin said chuck upon completion of sweeping by saidhydraulic broom.
 19. The cleaning apparatus as defined in claim 8,further comprising: a first motor for spinning said chuck, said firstmotor being controlled by said controller; a second motor forperiodically pivoting said hydraulic broom over a predetermined arc,said second motor being controlled by said controller; and wherein saidcontroller includes means for commanding said first motor to spin saidchuck and, concurrently, said second motor to periodically pivot saidhydraulic broom over said predetermined arc about a pivot axis andcommand said three-axis positioner to move said pivot axis of saidhydraulic broom along a straight line.
 20. The cleaning apparatus asdefined in claim 8, wherein each of said first and second adjustmentmeans is controlled by said controller, whereby said nozzle outlet isset to a height and said nozzle axis is set to an angle prescribed bysaid controller.
 21. The method of cleaning the surface of asemiconductor wafer comprising the steps of: (a) supporting said waferon a surface within an enclosure; (b) applying a sprayer to spray fluidsolvent at said wafer; and (c) moving said sprayer over the surface ofsaid wafer.
 22. The method of cleaning the surface of a semiconductorwafer defined in claim 21, wherein said step of moving said sprayer overthe surface of said wafer, further comprises the steps of (c1) movingsaid sprayer across the surface of the wafer from one side to the otherside at a first front to back position on said wafer, incrementing saidfront to back position of said sprayer from said first front to backposition, and moving said sprayer from said other side back to said oneside, further incrementing said front to back position of said sprayerfrom the immediately preceding first front to back position of saidsprayer, and moving said sprayer form said one side to said other side;and continuing the foregoing incrementing of the front to back positionof said sprayer and sideways moving of said sprayer, until the sprayerhas been incremented from the front to the back position of said waferand completed a last sideways movement to one side or the other side ofsaid wafer.
 23. The method of cleaning the surface of a semiconductorwafer defined in claim 22, further comprising the additional steps of:(d) rotating the wafer by ninety degrees; (e) moving said sprayer acrossthe surface of the wafer from one side to the other side at a firstfront to back position on said wafer, incrementing said front to backposition of said sprayer from said first front to back position, andmoving said sprayer from said other side back to said one side, furtherincrementing said front to back position of said sprayer from theimmediately preceding first front to back position of said sprayer, andmoving said sprayer form said one side to said other side; andcontinuing the foregoing incrementing of the front to back position ofsaid sprayer and sideways moving of said sprayer, until the sprayer hasbeen incremented from the front to the back position of said wafer andcompleted a last sideways movement to one side or the other side of saidwafer.
 24. The method of cleaning the surface of a semiconductor waferdefined in claim 23, further comprising the additional step of: spinningsaid wafer to remove liquid from the surface of said wafer.
 25. Themethod of cleaning the surface of a semiconductor wafer defined in claim21, wherein said step of moving said sprayer over the surface of saidwafer, further comprises the steps of: rotating said wafer; and,simultaneously, pivoting said hydraulic broom over a predetermined arcabout a pivot axis while moving said pivot axis along a linear path. 26.The method of cleaning a wafer of semiconductor material comprising thesteps of: sweeping said wafer with a hydraulic broom.
 27. The method ofcleaning a wafer of semiconductor material as defined in claim 26,further comprising the additional steps of: turning said wafer through apredetermined angle to reorient said wafer relative to said hydraulicbroom; re-sweeping said surface of said wafer with said hydraulic broom.28. The method of cleaning a wafer of semiconductor material as definedin claim 26, wherein said step of sweeping the surface of said waferwith a hydraulic broom further comprises the steps of: inclining saidhydraulic broom relative to said surface of said wafer to direct a jetof fluid issuing from said hydraulic broom at an angle toward saidsurface wherein said fluid may force any particles on said surfaceimpacted by said fluid to move away from said hydraulic broom; movingsaid hydraulic broom from side to side across said surface of said wafera predetermined number of times to push particulate material from saidsurface toward and off the back edge of said wafer, each said side toside movement of said hydraulic broom covering a different increment ofthe front to back distance of said wafer surface, whereby said hydraulicbroom sweeps the entire surface of said wafer after said predeterminednumber of said side to side movements of said hydraulic broom.
 29. Themethod of cleaning a wafer of semiconductor material as defined in claim28, wherein said hydraulic broom comprises: an aspirating nozzle. 30.The method of cleaning a wafer of semiconductor material as defined inclaim 28, wherein said hydraulic broom further comprises: an inlet forconnection to a source of pressurized gas; an aspirating inlet forconnection to a reservoir of a cleaning solvent; and a outlet forproducing an aspirated spray of gas and cleaning fluid.